1. Field of the Invention
The present invention relates to a device for opening or closing air vents of a car, and more particularly to a device for opening or closing air vents, which comprises a single opening/closing knob centrally installed between the left and right air vents, the opening/closing knob linked on both sides to left and right dampers so as to allow both the dampers to be simultaneously opened or closed with a single movement of the opening/closing knob, resulting in a reduction in the number of components and simplification of structure thus reducing manufacturing costs, and increasing convenience of use.
2. Description of the Related Art 
Generally, a car is equipped with an air conditioning system, which generates cool or warm air, supplying it to the passenger space of the car, thereby maintaining the temperature inside the car. For discharging the air into the passenger space, a plurality of air vents are provided inside the crash pad.
Considering the structure of a conventional car air vent 10, as shown in FIG. 1, a duct 1 is provided inside the crash pad of the car, upper and lower adjustment wings 3 are installed in front of the duct 1, and left and right adjustment wings 5 are installed inward relative to the upper and lower adjustment wings 3 adjacent thereto.
Further, in order to selectively intercept the outflow of air from the air vent 10, a damper 8 is installed within the duct 1.
The damper 8 is configured so as to be controlled according movement of the opening/closing knob 20, which is installed outside the air vent 10.
In the prior art, as shown in FIG. 2, a plurality of opening/closing knobs 20 must be provided in order to individually control the damper 8 provided in each air vent 10. This results in an increase of the number of components and difficulty in the assembly process thereof increasing the cost of manufacturing. Further, the plurality of the opening/closing knobs 20 is inconvenient to users since they  have to be individually operated.